Use and Care Manual
First Choice When Quality Matters
NORTH
AMERICA
Plunger Pumps
Operating Instructions and Parts Manual RC Series Pumps
Symptom Possible Cause(s) Corrective Action
Oil leak between
crankcase and pump-
ing section
Worn rod oil seals Replace crankcase piston rod
seals
Frequent or prema-
ture failure of the
packing
1 Cracked, damaged or worn
plunger
1 Replace plungers
2 Overpressure to inlet
manifold
2 Reduce inlet pressure
3 Material in the fl uid being
pumped
3 Install proper fi ltration on pump
inlet plumbing
4 Excessive pressure and/or
temperature of fl uid being
pumped
4 Check pressures and fl uid inlet
temperature; be sure they are
within specifi ed range
5 Running pump dry 5 Do not run pump without water
Pump runs but pro-
duces no fl ow
Pump is not primed Flood suction then restart pump
Pump fails to prime Air is trapped inside pump Disconnect discharge hose from
pump. Flood suction hose,
restart pump and run pump until
all air has been evacuated
Pump looses prime,
chattering noise,
pressure fl uctuates
1 Air leak in suction hose or
inlet
1 Remove suction line and inspect
it for a loose liner or debris
lodged in hose. Avoid all unnec-
essary bends. Do not kink hose
2 Clogged suction strainer 2 Clean strainer
Low pressure at
nozzle
1 Unloader valve is by-pass-
ing
1 Make sure unloader is adjusted
property and by-pass seat is not
leaking
2 Incorrect or worn nozzle 2 Make sure nozzle is matched
to the fl ow and pressure of the
pump. If the nozzle is worn,
replace
3 Worn packing or valves 3 Replace packing or valves
Pressure gauge fl uc-
tuates
1 Valves worn or blocked by
foreign bodies
1 Clean or replace valves
2 Packing worn 2 Replace packing
Low pressure 1 Worn nozzle 1 Replace with nozzle of proper
size
2 Belt slippage 2 Tighten or replace with correct
belt
Troubleshooting
Plunger Pumps
Operating Instructions and Parts Manual RC Series Pumps
First Choice When Quality Matters
NORTH
AMERICA
Symptom Possible Cause(s) Corrective Action
Low pressure (cont.) 3 Air leak in inlet plumbing 3 Disassemble, reseal and reas-
semble
4 Relief valve stuck, partially
plugged or improperly
adjusted valve seat worn
4 Clean and adjust relief valve;
check for worn or dirty valve
seats
5 Worn packing. Abrasive
in pumped in cavitation.
Inadequate water
5 Install proper fi lter suction at
inlet manifold must be limited to
lifting less than 20 feet of water
or 8.5 psi vacuum
6 Worn inlet, discharge valve
blocked or dirty
6 Replace inlet and discharge valve
Pump runs extremely
rough, pressure very
low
1 Inlet restrictions and/or air
leaks.
1 Clean out foreign material
2 Stuck inlet or discharge
valve
2 Replace worn valves
Water leakage from
under manifold
Worn packing or cracked
plunger
Install new packing or plunger
Slight leak, oil leak-
ing in the area of
crankshaft
1 Worn crankshaft seal or
improperly installed oil seal
o-ring
1 Remove oil seal retainer and
replace damaged 0-ring and/or
seals
2 Bad bearing 2 Replace bearing
Excessive play in the
end of the crankshaft
pulley
Worn main bearing from
excessive tension on drive
belt
Replace crankcase bearing and/or
tension drive belt
Water in crankcase 1 Humid air condensing into
water inside the crankcase
1 Change oil intervals
2 Worn packing and/or
cracked plunger
2 Replace packing. Replace
plunger
Loud knocking noise
in pump
1 Cavitation or sucking air 1 Check water supply is turned on
2 Pulley loose on crankshaft 2 Check key and tighten set screw
3 Broken or worn bearing 3 Replace bearing
Troubleshooting (cont.)